Note: Descriptions are shown in the official language in which they were submitted.
CA 02595326 2011-01-25
DEVICE FOR MILLING ROCK AND OTHER MATERIALS AND METHOD
FOR MILLING ROCK OR THE LIKE USING SAID DEVICE
The invention relates to a device for milling treatment, in particular, rock
or other materials, with a
spindle drum which is rotatably mounted on a drum support about a drum axis,
in which a plurality of
tool spindles are supported eccentrically to the drum axis to be rotatably
drivable about spindle axes and
carry machining tools at their ends projecting from the spindle drum. The
invention further relates to a
method for milling rock or the like using such a device.
For the milling of rock or other hard materials as for example of extraction
products in underground or
open-work mining, of tarmac or concrete components in road or structural
engineering, a plurality of
milling systems are known, which are mainly rotary driven drums or discs, at
the circumference of which
are mounted milling tools, for example round shaft bits, in an evenly
distributed manner. If rock or coal
is extracted in underground mining with such a drum provided with milling
tools at its circumference, for
example with the help of a drum shearer loader, and the cutting disk or drum
cuts or mills the material to
be extracted with a full face cut, approximately half of all machining tools
arranged at the circumference
of the drum are engaged simultaneously. Each machining tool is engaged with
the material to be
machined during the full face cut via half a rotation, that is 180 , which
results in that the hard metal tips
of the tools are heated to very high temperatures and wear quickly, especially
in harder materials.
A further disadvantage with the known machines consists in that the entire
contact pressure, with which
the drum abuts against the rock, is distributed onto a large number of
individual tools, so that for every
individual chisel in use, only a comparatively small pressure force is
available. If the entire pressure of
the drum against the rock is for example about 2000 N, and about 20 individual
tools are always used
during a full cut, on the average every individual tool has only a contact
pressure of 100 N . Furthermore,
it is also difficult to axially drive into the material to be machined with
the known devices, in which the
tools are drivingly connected at the circumference of a roller or a drum,
which problem can be attributed
to the fact that the optimum cutting speed is at the outer diameter of the
drums, and that the cutting speed
is consistently reduced in the direction towards the axis of rotation of the
drum or the roller, and becomes
so small in the proximity of the axis of rotation, that cutting is practically
impossible there. Even when
the drum is provided with tools at its face side, these cannot break out the
rock abutting their face during
the axial driving-in of the drum in a reasonable manner.
From DE 34 45 492 C2, a boring head for boring in rock is known, which
comprises a tool support with
boring tools, which is mounted on a central shaft, which is coupled to bore
rods extending between the
bore hole and the boring head. The boring tools at the tool support can be
rotatably driven via a planetary
gear transmission.
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It is a feature of the invention to create a device for the milling treatment
of rock or
other materials of the above-mentioned type, which is able to also treat very
hard
materials with a high milling performance, whereas, compared to conventionally
driven
tools, the pressing forces exerted by the spindle drum are reduced and the
edge lives of
the tools are extended. Particularly, the device according to invention shall
have a high
operational security, be compact and offer the possibility to receive
machining tools of
different types as for example milling rollers, saw blades, undercutting tools
or the like
with arbitrary weights and sizes.
In accordance with an embodiment of the present invention there is provided a
device
for milling treatment of rock and other materials, with a spindle drum
rotatably
mounted on a drum support about a drum axis, in which spindle drum several
tool
spindles are pivotally-mounted about spindle axes which are eccentric from the
drum
axis, the tool spindles carrying machining tools at their ends projecting from
the spindle
drum, wherein at least two of the tool spindles can be driven via a common
transmission gear drive which comprises driven gear wheels drivingly connected
to the
tool spindles and a common drive element which cooperates with the driven gear
wheels, the drive element and the spindle drum being arranged to rotate
relative to one
another, and wherein one machining tool arranged at one of the tool spindles
is
arranged offset an angular amount relative to an arrangement of one machining
tool of
a tool spindle lying in front or behind thereof in a circumferential direction
of the drum,
so that the machining tools of tool spindles following each other in the
circumferential
direction of the spindle drum are arranged in a phase-shift manner with regard
to one
another.
Another embodiment of the present invention provides a method for milling rock
using
a device of the invention where the rotary speed of the tool spindles and the
rotary
speed of the spindle drum or the angular position of the individual tools
arranged at the
individual tool spindles are adjusted relative to the angular position of the
individual
tools of the tool spindles lying in front or behind thereof in the
circumferential direction
so that an individual tool of a following tool spindle does not impact the
rock or the like
at the same point of impact as an individual tool of a preceding workpiece
spindle.
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As at least two of the tool spindles can be driven by a common transmission
gear drive, which comprises
driven gear wheels drivingly connected to the tool spindles and a common drive
element, in particular a
drive gear wheel or also a drive chain, a drive transmission belt or the like,
which drive element
cooperates with the driven gear wheels, while the drive element and the
spindle drum can be rotated
relatively to one another, a particularly compact arrangement of a device is
created, in which the at least
two tool spindles with the tools thereon are driven synchronously outside the
centre axis of the spindle
drum. The machining tools arranged at the tool spindles can thereby be
adjusted easily so that even
during a full cut with an abutment of 180 respectively only one machining
tool or only a few tools are
used simultaneously, so that the entire available pressing force of the
spindle drum can respectively only
be used by one or a few tools, that is, the individual tool presently in
engagement with the rock has a
very high loosening force.
It is possible that the spindle drum comprises a rotary drive, which is
decoupled from the transmission
gear drive. In this embodiment, the spindle drum is thus rotated by a rotary
drive and the tool spindles
experience their drive independently of the rotary speed of the spindle drum.
With this embodiment, it is
even feasible to stop the spindle drum in any case briefly during the axial
drive-in of the device into the
rock and to bore a short distance into the rock only by rotation of the tool
spindles, and only then to start
the drive for the spindle drum.
It has proved to be particularly advantageous if the spindle drum and at least
some of the tool spindles
have a common rotary drive, so that, with a rotation of the spindle drum, the
tool spindles which are also
acted upon by the common rotary drive are also automatically rotated.
In this context, it is constructionally advantageous if the drive element
formed from a drive gear wheel is
arranged irrotationally with respect to the drum support, in particular firmly
connected to the drum
support. The driven gear wheels drivingly connected to the tool spindles then
mesh with the drive gear
wheel arranged irrotationally with respect to the drum support, whereby the
tool spindles are rotated
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when the spindle drum in which the tool spindles are received is driven by the
rotary drive. Very high
forces and torques can be transferred with such a planetary gear drive with a
particularly compact design.
The tool spindles are preferably received in bearing bushes by means of
bearings in a rotary manner and
are conveniently sealed by shaft seals. It is particularly advantageous with
such an arrangement, if the
bearing bushes with the tool spindles mounted therein in a rotary manner are
inserted and locked in an
exchangeable manner like cartridges in drum chambers provided at the spindle
drum. The tool spindles
can then be replaced with their bearings and possibly seals by simple exchange
of the bearing bushes in
the structural unit, for example when they are worn or when tool spindles for
other machining tools are to
be used. The tool spindles in the bearing bushes are pre-mounted, so that
removal and fitting of this
structural unit only takes a very short time.
Preferably, all tool spindles can be drivable via the common drive gear wheel
of the transmission gear
drive. However, it is also easily possible that a first group of tool spindles
is drivable via a first common
drive gear wheel and a second group of tool spindles is drivable via a second
common drive gear wheel,
for example in a case in which a first group of tool spindles is arranged at
the spindle drum on a pitch
circle having a larger diameter and a second group of tool spindles is
arranged on a pitch circle having a
smaller diameter. The gear transmission ratios between the tool spindles of
the first group and the first
drive gear wheel and the tool spindles of the second group and the second
drive gear wheel and/or the
directions of rotation of the tool spindles of the first and second group can
then be different. As already
suggested above, the tool spindles of the first group and those of the second
group can be arranged with a
different radial distance from the drum axis in the spindle drum, that is, on
two different pitch circles.
The tool spindles are preferably arranged uniformly distributed over the
circumference in the spindle
drum.
In a particularly advantageous embodiment of the device according to invention
it is possible that the
machining tool(s) of one tool spindle is/are arranged in an offset manner
relative to the arrangement of
the machining tool(s) of the tool spindle being arranged in front or behind
that one tool spindle in the
drum circumference direction. In other words, the machining tools of tool
spindles following each other
in the circumferential direction of the spindle drum can be arranged with
regard to one another in a
phase-shift manner. This arrangement makes it possible to ensure in a
particularly advantageous manner
during the execution of the method according to the invention for milling of
rock, that an individual tool
arranged at a tool spindle reaches engagement with the rock to be machined at
another point than an
individual tool of a tool spindle lying in front of it in the direction of
rotation. It is thus ensured by the
phase-shifted arrangement of the tools that the impact points of the
individual tools or cutters of the
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different tool spindles do not overlap, but that a following tool machines the
rock at a point which the
tools of a tool spindle moved previously through the rock have left. Thereby a
particularly effective
treatment of the rock or the like is achieved. In order to achieve the desired
phase shift or the offset angle
as exactly as possible, the machining tools are preferably arranged in an
adjustable manner at the tool
spindles, that is, they can be adjusted in their angular position relative to
the tool spindles.
The machining tools can comprise one or several machining bits or individual
tools at every tool spindle.
In a particularly advantageous embodiment of the invention, at least some of
the individual tools can
consist of straight shank bits, while in some cases, flat chisel tools or
roller bits have proved themselves,
in particular roller bits which are formed conically on one side. For many
machining uses it has proved to
be advantageous if the machining tools project at the most with 50% of their
machining surfaces radially
over the outer circumference, that is, that at the most half of the individual
machining tools of a tool
spindle are in simultaneous engagement with the rock or the like.
The spindle drum can be provided with a preferably centrically arranged dust
extraction opening, through
which the fine dust which results during the milling treatment of the rock or
the like can be extracted. It
is also advantageous, if the device is provided with at least one sprinkling
device for the machining tools,
with which on the one hand the resulting dust can be bound by water sprayed on
the machining point,
and on the other hand, a cooling of the machining tools can be provided. The
sprinkling device is
preferably arranged at the spindle drum and/or at the drum support.
With the device according to invention, machining tools of different types can
be used. It is thus possible,
when the machining tools of one or several of the tool spindles essentially
consist of a chisel support and
several round bits, flat bits and/or roller chisels arranged thereon, whereas
the arrangement is in such a
manner that the chisel/bit tools arranged at the chisel support machine the
rock or other respectively
machined material in an undercutting manner in one or more layers. The
arrangement is preferably made
in such a manner that a tool operating in several layers tapers in the
direction of the rock to be machined,
preferably in the form of steps. The machining tools can essentially also
consist of milling rollers, which
are arranged on one or several tool spindles. These milling rollers can be
formed cylindrically or can
taper conically or expand towards the rock to be machined.
If the drive element consists of a drive gear wheel geared on the outside,
which is connected to the drum
support, the direction of rotation of the tool spindles is the same as the one
of the spindle drum. If the
drive element consists of a drive gear wheel geared on the inside, the tool
spindles driven from such a
drive gear ring rotate in the opposite direction of the spindle drum.
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In order to provide the rotary drive for the spindle drum independent from the
transmission gear drive
for the tool spindles, a constructional embodiment has proven to be
advantageous, in which the spindle
drum comprises a reception bore for a drive shaft running coaxially to the
drum axis, which drive shaft is
rotatably supported in the reception bore and is coupled to the drive element
for the tool spindle. The
drive shaft is thus mounted rotatably concentrically in the spindle drum,
which is not only particularly
compact, but which also ensures a high stability of the construction. The
spindle drum can comprise a
closed housing with an approximately cup-shaped drum base and a housing lid,
so that the drive element,
that is, in particular the drive gear wheel, is received in the inside of the
drum base and is connected to
the drive shaft and is covered by the housing lid.
The transmission drive for the tool spindles is preferably arranged in an
encapsulated manner in the
spindle drum. The machining tools with their respective tool spindles can be
in an overhung position at
the spindle and can project from the spindle drum at the face and/or at the
circumference.
So as to favour the axial driving-in of the device into the rock, it has been
proved to be advantageous if
the spindle drum is, additionally to the tool spindles which are arranged
distributed over its
circumference, provided with milling tools with a core milling cutter arranged
in the inside of the pitch
circle described by the tool spindles, which core milling cutter is preferably
arranged with a small
eccentricity to the drum axis. With the help of the core milling cutter which
is formed in a driveable
manner, it can be ensured that the entire rock present in front of the face of
the spindle drum will be
milled during the axial feed motion of the device therein.
In order to ensure a particularly stable reception of the tool spindles, the
machining tools with their
respective tool spindles are preferably mounted at the spindle drum by means
of a two-point bearing. A
fixed floating bearing can be provided for this, alternatively, an engaged
bearing, in particular in the X-
arrangement can be used, for example by means of taper roller bearings or the
like.
Especially in cases where machining tools with a comparatively large axial
length are to be used, for
example tools with long milling shanks, it is particularly advantageous if the
spindle drum comprises an
approximately plate-like bearing flange in the proximity of the drum support
for the reception of the first
bearings of the tool spindles and a support journal projecting concentrically
to the drum axis, at which at
least one support element for the reception of the second bearings of the tool
spindles is arranged. The
regions of the machining tools which machine the rock are then between the two
bearings, so that a
particularly sturdy support is achieved. With this embodiment of the invention
it can further be
convenient, that the support element or the support journal comprises a
bearing journal arranged
concentrically to the spindle drum axis for the additional support of the
spindle drum. Thereby it is then
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possible to also mount the spindle drum itself by means of a two-point
bearing, that is to additionally
support it at the end which is turned away from the drum support, and
therewith to avoid bending which
can occur with long tools and an overhung bearing.
The support element can consist of a lid flange arranged at the face of the
support journal, which flange
is provided with bearing receptions for the second bearing. The machining
tools are then covered by the
lid flange at their face and machine the rock only with individual tools which
are arranged at their
circumference and which project radially between the plate-like bearing flange
and the lid flange of the
spindle drum therefrom. It is also possible that at least two support elements
are provided, which are
arranged at different distances from the bearing flange and which respectively
receive the second
bearings of different tool spindles. With this arrangement, the second
bearings of the tool spindles then
have a distance from the face (free) end of the machining tools, which can
then also be in engagement
with the rock with their faces.
So as to avoid damages of the device by overloading, it has proved to be
convenient that the drive
element is connected to the drum support via an overload clutch, which can for
example be a spring-
loaded friction clutch. The spring load acting on the clutch is preferably
adjustable, so that the activation
value at which the clutch is released and the drive element slips through at
the drum support can be
adjusted.
The spindle drum can, at its rear side, which is turned away from the
machining tools, be provided with a
demountable covering cap sealed with regard to the drum support by means of a
shaft seal, which cap
enables access to the transmission gear drive and other parts lying below,
which have to be serviced or
inspected occasionally.
Generally, the tool spindle axes in the spindle drum will be aligned parallel
to the drum axis. It is
however also possible to arrange the tool spindle axes in an inclined manner
relative to the drum axis,
whereby the milling result can be improved further with some rocks or
materials to be machined. In a
further embodiment of the invention, every machining tool preferably comprises
several individual tools
arranged evenly over the circumference of the machining tool, and is mounted
to the associated tool
spindle using a detent coupling, whereby the number of possible lock positions
of the detent coupling is
adapted to the number at the machining tool so that these are in the same
relative position to the tool
spindle in every locked position. The detent coupling responds when the
machining tool is blocked by
the rock which it engages, so that the associated tool spindle which carries
this tool can rotate further to
the next lock position, into which the machining tool then locks again and
rotates further. The machining
tool thereby locks again in such a position where its relative position to the
machining tools of adjacent
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tool spindles remains the same, that is, the originally adjusted phase shift
or the offset of the machining
tools of successive tool spindles remains after the response of the detent
coupling and locking of the tool.
The device according to invention and the method that can be effected thereby
are particularly suitable
for the removal of mineral extraction products as for example coal, ore rock
or the like. The device can
be used for this purpose as replacement for a well-known cutting head of a
drum shearing machine or as
cutting head of a selective cut or full cu heading machine. The device and the
method can
advantageously also be used for the machining of concreted or tarmacked
surfaces or buildings, for
example when milling tarmacked or concreted road surfaces, during demolition
of concrete buildings or
the like. It is often advantageous for the different applications if the
device according to the invention is
mounted to an adjustable arm and is engaged with this against the rock or the
like to be machined. Use of
the device according to the invention is also conceivable with small
appliances, for example with hand-
held plaster milling devices.
Further characteristics or advantages of the invention result from the
following description and the
drawings, where preferential embodiments of the invention are explained
further with examples It shows:
Fig. 1 a first embodiment of a device according to the invention in cross
section (fig. 1 a) and plan view
on the spindle drum;
Fig. 2 a second embodiment of the device according to the invention in a
representation corresponding to
fig. 1;
Fig. 3 a third embodiment of the device according to the invention in a
representation corresponding to
fig. 1 and 2;
Fig. 4 a fourth embodiment of the device according to the invention in a
representation corresponding to
fig. 1 to 3;
Fig. 5 a device according to invention during the implementation of the method
according to the
invention in contact with the rock in a view on the spindle drum and partially
in cross section;
Fig. 6 a fifth embodiment of the device according to the invention in cross
section;
Fig. 7 a sixth embodiment of the device according to the invention, also in
cross section;
Fig. 8 a seventh embodiment of the device according to the invention;
Fig. 9 an eighth embodiment of the device according to the invention;
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Fig. 10 a ninth embodiment of the device according to the invention in a
representation corresponding to
fig. 1 to 4;
Fig. 11 a tenth embodiment of the device according to the invention in cross
section;
Fig. 12 an eleventh embodiment of the device according to the invention in a
representation
corresponding to fig. 1 to 4;
Fig. 13 a twelfth embodiment of the device according to the invention in a
representation corresponding
to fig. 1 to 4; and
Fig. 14 a thirteenth embodiment of the invention;
The various embodiments of the device according to the invention shown in the
drawings, which device
is designated as 10 in its entirety, serve for the milling of rock, for
example mineral extraction products
such as coal or ore, or also for the processing of concrete, tarmac or other
building materials, for example
during the milling of road surfaces or the like. As far as the different
embodiments of the device
according to the invention conform in their constructional details, a repeated
description of these
recurring details with different embodiments shall be forgone. Rather, after
the detailed description of the
fundamental construction on the basis of fig. 1, essentially only the
differences of the different
embodiments will be explained.
Referring to fig. 1, it can be seen that the device 10 according to the
invention comprises a drum support
11 for the mounting to a machine body (not shown) suitable therefore, for
example an extension arm of a
winning machine or a road milling machine. The drum support 11 comprises a
central bearing reception
12, in which a spindle drum 13 is pivoted by means of two taper roller
bearings 15 adjusted in a back-to-
back arrangement. The bearing journal 14 projects with its rear end 16 from
the bearing reception 12 of
the drum support 11 rearwardly and supports a drive wheel 17 there which is
coupled to a rotary drive for
the rotation of the spindle drum, not shown in detail.
The bearing journal 14 changes into a circular plate-like bearing flange 18 of
the spindle drum at its other
end opposite the drive wheel 17, which journal comprises several, in the
example of the embodiment six,
evenly distributed drum chambers 20 on a pitch circle 19 near its outer
circumference. The drum
chambers 20 each receive a bearing bush 21 with a tool spindle 22 mounted
rotatably therein, whereby
the bearing bushes with the tool spindles mounted therein like a cartridge are
inserted into their
respective drum chamber 20 in an exchangeable manner and are locked in the
inserted state by means of
fixing screws 23. At their rear end, with which the tool spindles project
rearwardly from the bearing
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flange 18 of the spindle drum, they are provided with driven gear wheels 24
which mesh with a driving
gear wheel 25, which is secured firmly to the drum support 11 with screws 27
at a gear wheel reception
26 provided for this. One can see in the first embodiment shown in fig. 1,
that the gearings of the driven
gear wheels 24 of the tool spindles 22 roll off at the drive gear wheel 25
firmly mounted to the drum
support 11, when the spindle drum 13 is rotated by the rotary drive effective
at the drive wheel 17, so that
the tool spindles are also rotated hereby. With this design, there exists a
fixed gear transmission ratio
between the rotatably driven spindle drum 13 and the tool spindles
synchronously driven by the gear
drive 24, 25 pivoted therein. . With a gear transmission ratio of for example
10:1, the tool spindles rotate
with 500 rpm when the spindle drum is driven with 50 rpm. The gear
transmission ratio can be changed
by a change of the diameters of the drive gear wheels and of the driven gear
wheel or a change of the
number of teeth. To this end, the drive gear wheel 25 can be disassembled and
can be replaced by for
example by a smaller gear wheel, while also other tool spindles with
correspondingly larger drive gear
wheels are inserted at the same time.
For the attachment of the entire device 10 to a machine frame (not shown)
provided for this, as for
example an arm of a drum shearing machine or a road milling machine, mounting
holes 28 for fixing
screws are provided at the drum support 11, which screws are threaded through
access holes 29 provided
in the bearing flange 18 of the spindle drum and can be screwed into threaded
bores at the machine frame
aligned with the mounting holes 28 by means of a suitable tool as for example
an allen key. The entire
device can be quickly installed at the machine frame without disassembly of
any parts of the device.
In fig. IA it can easily be seen that the bearing flange 18 of the spindle
drum 13 is provided with a
housing lid 30 at its rear side, which is screwed to the bearing flange 18 and
together with this forms a
closed housing 31 for the transmission gear drive 24, 25 of the tool spindles.
In order to prevent an
ingress of humidity or dirt into the housing 31, the housing lid 30 is
provided with a seal 32 at its radial
inner edge, with which the sealing with regard to the drum support is
effected.
The front ends of the tool spindles projecting from the free side of the
spindle drum form cone seat
receptions 33 for machining tools, different designs of which being shown in
fig. 2 to 14. All these
different designs of the machining tools can also be used with the embodiment
of the design according to
the invention according to fig. 1, as will be described in detail in the
following.
With the embodiment of the invention shown in fig. 2, it is possible to adjust
the number of revolutions
and the direction of rotation of the individual tool spindles independently of
the number of revolutions
and the direction of rotation of the spindle drum. For this, the spindle drum
13 comprises a rotary drive,
which is decoupled from the transmission gear drive of the tool spindles. This
is solved constructionally
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in that the spindle drum 13 comprises a reception bore 35 for a drive shaft 36
running coaxially to the
drum axis 34, which shaft is mounted in the reception bore in a rotary manner
with two cylinder roller
bearings 37. The front bearing flange 18 of the spindle drum forms a closed
housing 31 with an
approximately cup-shaped drum base 38 and a housing lid 30, and the drive gear
wheel 25 of the
transmission gear drive for the tool spindles is irrotationally mounted on the
drive shaft 36 and is
received in the housing 31 between the drum base 38 and the housing lid 30.
There it meshes with the
driven gear wheels 24 of the tool spindles 22.
The drive shaft is provided with a front gear wheel 39 at its rear end, which
can be coupled to a spindle
drive motor (not shown), so as to rotate the drive shaft 36 and thus the drive
gear wheel 25 mounted
thereon on the inside of the spindle drum and to hereby effect the rotary
drive of the tool spindles, so that
the number of revolutions of the tool spindles can be adjusted independently
of the number of revolutions
of the spindle drum.
In the embodiment according to fig. 2, the tool spindles are not received in
bearing bushes and inserted
cartridge-like in drum chambers at the spindle drum, but the individual shafts
are mounted directly in the
spindle drum, whereas the rear of respectively two cone roller bearings is
arranged in the drum base and
the front bearing pointing to the machining side in the housing lid 30. The
sealing of the spindle drum in
relation to the drum support 11 is effected by means of a shaft seal ring 40
in this example of the
embodiment, which is arranged in the transition region of the bearing flange
18 to the bearing journal 14.
With the example of an embodiment according to fig. 2, chisel rings 42 with
respectively six individual
tools 43 in the form of impact chisels mounted thereon are used as machining
tools 41, whereas the
arrangement is such that the sphere of activity 45 defined by the impact tips
44 of the individual tools 43
projects with a relatively small segment over the outer circumference 46 of
the spindle drum, so that,
with the example of an embodiment shown, no more than two individual tools 43
project radially over
the outer circumference 46 of the spindle drum at the same time. The circle
line 4 describing the
individual spheres of activity 45 of the six machining tools 41 defines the
milling diameter of the device
in the rock, that is, the range within which the machining tools machine the
rock with their individual
tools. It can be seen that no more than 1/3 of all individual tools are
engaged at the milling line 47 in the
rock at a respective time, that is, every tool only breaks out rock on 1/3 of
the path covered by a rotation
of the tool spindle and is subjected to the loads created thereby.
Fig. 3 shows the device according to fig. 2, as provided with machining tools
41 in the form of conical,
two-stage chisel milling cutters 48, which respectively comprise six
individual tools 43 at axially
successively arranged mounting circles. The chisel milling cutters mill
through the rock 49 in two stages
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during the operation of the device, so that the radially external machining
tools impact the rock 49 in a
first sphere of activity 46a closer to the device, and the radially inner
tools in a second sphere of activity
46b which establishes deeper in the rock. It can easily be seen that, by the
overlapping of the rotation of
the spindle drum 13 and the rotation of the tool spindle, the individual tools
43 are actually engaged with
the rock only for a short time, whereby the wear of the tools is considerably
reduced in a particularly
advantageous manner compared to known cutting drums or the like. Instead of an
arrangement in two
stages, an arrangement in three or more stages can of course also be selected
for the individual tools, in
order to remove the rock or another material to be milled in one operation by
a direction-free, lateral
method of the device in an undercutting manner. An axial driving-in of the
device into the rock is
generally possible without any problem.
With embodiment shown in fig. 4, the machining tools are end milling cutters
50, which comprise a
support shaft 51 connected rigidly to the respective tool spindle 22, at the
circumference of which are
arranged individual tools 43, which can for example consist of straight shank
chisels received in suitable
tool holders. The individual tools are preferably arranged in a spiral form
over the length of the support
shaft 51 in this embodiment, while the arrangement can also take place in
several spirals. With this
arrangement, it is easily possible to drive axially into the material to be
cut, and subsequently to remove
the material in the entire driven depth or length of the shaft milling cutters
by a direction-free, lateral
method of the device. So as to ease the cutting, that is, the driving-in in
the axial direction, it is possible
to taper the diameter of the tools at least at their front region towards the
face in the direction of the rock.
In fig. 5, the preferred mode of operation which can be achieved with the
device according to the
invention can be seen in a particularly illustrative manner. While the spindle
drum rotates with a first
rotation speed in the direction of arrow A, for example with 50 rpm, the
individual tool spindles rotate
synchronously with a rotation speed corresponding to the chosen gear
reduction, that is, with the
embodiments of the device according to fig. 1, 3 and 4, in the same direction
of rotation as the spindle
drum. With an assumed gear transmission ratio of 1: 10, the rotation speed of
the tool spindles is thus
500 rpm. It can be seen that the first machining tool 41A, which impacts the
rock 49 to be milled,
impacts recesses 52 into the rock 49 with its four individual tools 43 with a
certain rhythm or distance.
The following machining tool 41B drives rock out between the recesses 52,
whereby a wave profile 54 is
formed in the rock at the approximately semicircular milling edge 53. The
machining tools 41C and 41D
following now successively remove the raised tips 55 in the wave profile,
shown in a hatched
representation, whereby the milling edge is smoothed as far as possible, and
with the further feed of the
spindle drum in the direction of the arrow 56, the described procedure with
the machining tools 41E to
41H can repeat itself. Alternatively, the tools 41E-H can also even be used
for a further smoothing of the
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milling edge 53 in the rock. On the other hand, it is also possible, depending
on the chosen gear reduction
ratio and number of the individual tools 43 at the machining tools, that a
first machining tool, for
example tool 41 A, pre-cuts, and that the regions remaining between the
recesses 52 are knocked off with
the following tool, and that the tool following in the circumferential
direction of the drum then again
drives out new recesses 52 as the first tool and that the following tool mills
the regions remaining
therebetween. The representation according to fig. 5 is selected as if the
tools 41A-D drive approximately
simultaneously into the rock 49 to be cut, which is normally not the case in
practice. It has proven to be
particularly advantageous in experiments, if the tools - in the shown case the
machining tools 41A-H - are
constructed in such a manner, that, with the shown engagement of 180 (full
cut) only one individual tool
of all (five) effective machining tools is in engagement with the rock on the
180 region of the milling
edge 53, as then the entire pressing force or feeding force exerted on the
spindle drum by the device can
be used by only one individual tool, and not, as was usual up to now, is
distributed simultaneously on
several bits. The machining tools are positioned and adjusted in the preferred
form so that the tools
following in each case do not drive exactly into the outline produced by the
preceding tools at the rock,
but in an offset manner.
A further embodiment of the device according to the invention is shown in fig.
6. This embodiment is
based on the device according to fig. 1 and differs from this by the mounting
of the drive gear wheel 25,
at which the driven gear wheels 24 of the tool spindles roll off. In the
embodiment according to fig. 6, the
drive gear wheel 25 is connected to the drum support 11 via an overload clutch
57, which effects a
friction-locked connection between the drum support 11 and the drive gear
wheel 25 via clutch linings
58. The activation moment where the overload clutch operates and the drive
gear wheel begins to slip
through with regard to the drum support can be adjusted. For this, an
adjustment ring 59 can be engaged
against the clutch package formed by the clutch linings and the intermediate
part of the drive gear wheel
via a thread 60, in order to preload a plate spring 61 which then acts thereon
with a constant spring
25 load over the circumference of the clutch. With this arrangement, it is
ensured that the device is not
damaged when a tool driving into the rock blocks, as in such a case, the
overload clutch responds and
separates all machining tools from the common drive of the spindle drum and
the tools until the blocking
of the concerned individual tool ceases. The synchronisation of the individual
machining tools with one
another still remains , as these all stay in engagement with the driven gear
wheel during the activation of
the clutch.
The embodiment of the device according to the invention shown in fig. 7 also
uses the overload clutch,
which is designed exactly as with the embodiment according to fig. 7. In the
embodiment shown in fig. 7,
however, there is selected a separate drive from the spindle drum drive for
the tool spindles. For this, a
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drive ring 62 is mounted in a rotary manner at the drum support 11 at a front
section 11 a, which ring
supports the drive gear wheel mounted via the overload clutch 57 at its outer
circumference. The drive
ring is provided with an internal gearing 63 at it axial rear region, into
which gearing engages a drive
pinion (not shown) of a common tool drive, so as to effect the rotation of the
drive ring on the drum body
11, and to drive the tool spindles hereby.
Fig. 8 again shows the device according to fig. 1, this time with machining
tools in the form of cutting
plates 64, which essentially consist of an approximately plate-shaped support
65 and respectively four
cutting discs 66 arranged evenly over the circumference of the support 65,
which discs are rotatably
mounted in the support 65. The arrangement is such that the axes of rotation
of the discs 66 do not run
parallel to the axis of rotation of the support 65 mounted irrotationally on
the associated tool spindle, but
are inclined inwardly towards the rock, so that during the cut of the cutting
discs into the rock 49 the
faces of the cutting discs do not come into contact with the rock, but that it
is ensured that the cutting
discs 66 actually only machine the rock with their rotating cutting edge 67.
By the rotary mounting of the
cutting discs in the support of the cutting plates it is ensured that the
cutting discs can roll off in the rock
along their cutting edge at the generated milling edge 53. In a preferred
further development of this
embodiment, not shown, the individual cutting discs can be coupled to one
another via a suitable
coupling tool as for example a belt transmission or a gear wheel transmission
present in the inside of the
support, whereby it is ensured that, during the rotation of the tool spindle,
an individual tool (cutting
disc) coming into engagement with the rock already comprises the same
circumferential speed, as a
preceding individual tool leaving the engagement, so that a possible damage
does not occur here by the
sudden acceleration of the cutting disc during contact with the surrounding
rock. The machining tools
which are used in the embodiment according to fig. 8 are particularly suitably
for somewhat softer rocks
to be machined, for example during the production of coal.
With the embodiment shown in fig. 9, the spindle axes 68 of the tool spindles
22 are not aligned parallel
to the drum axis 34 of the spindle drum 13, but are inclined inwardly in the
direction of the rock. For this,
the bearing bushes 21 are bored diagonally for the reception of the tool
spindles mounted therein and the
drive gear wheel 25 is a formed as a bevel gear, at which the driven gear
wheels 24 of the diagonal tool
spindles formed at the tool spindles roll off.
With the embodiment of the device according to the invention according to fig.
10, the tool spindles 22
are arranged on two different pitch circles 19a, 19b, as can easily be seen in
fig. 10. The drive of the first
group 69 of tool spindles on the first, outer pitch circle 19a and of the
second group of 70 of tool spindles
on the inner pitch circle 19b takes place through a common drive element in
the form of a stepped drive
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gear wheel 25, which comprises a first gear ring of larger diameter 25a for
the tool spindles of the first
group lying outside and a second gear ring 25b with smaller diameter, which
drives the tool spindles of
the second group 70 which lie radially somewhat further inside. In all other
respects, the structure of the
embodiment according to fig. 10 corresponds to the one used with fig. 1.
With the embodiments of the device according to the invention described up to
now with a common
drive for the spindle drum and the tool spindles mounted rotatably therein,
the direction of rotation of the
spindle drum and the tool spindles was the same. Fig. 11 now shows an
embodiment where the tool
spindles rotate against the direction of rotation of the spindle drum 13. For
this, the drive element for the
tool spindles consists of a drive gear ring 71 geared on the inside, which is
centrally fastened to the drum
support 11 and in which engage the tool spindles with their driven gear wheels
24, as can be seen in the
drawing.
With the embodiments shown in fig. 12 and 13, shaft milling cutters with a
comparatively long support
shaft 51 are used as machining tools 41, which cannot, due to the large axial
length of the tools, be
overhung alone like the embodiments shown so far. Accordingly, with the
embodiments according to fig.
12 and fig. 13, the machining tools are mounted at the spindle drum with their
respective tool spindles by
means of a two-point mounting. The spindle drum comprises a plate-like bearing
flange 18 in the
proximity of the drum support 11 for the reception of the first bearings of
the tool spindle for this, which
form the fixed bearing for the two-point bearing with the shown embodiment and
which is executed in
the form of a mounted bearing in a back-to-back arrangement with cone roller
bearings. The spindle
drum further comprises a projecting support journal72 arranged concentrically
to the drum axis 34
which supports a support element 73 for the reception of the second bearings
74 of the machining tools
arranged on the tool spindles near its free end. With embodiments according to
fig. 12 and fig. 13, the
second bearings at the support element form the floating bearing for the fixed
floating bearing of the
machining tools. They consist of cylinder roller bearings, which are
particularly suitable for the reception
of large radial forces. With the embodiment according to fig. 12, the support
element consists of a lid
flange 75 arranged at the face of the support journal 72, which flange is
provided with bearing receptions
76 for the cylinder roller bearings 74. This embodiment of the two-point
bearing for the machining tools
is particularly stable, but it is not suitable for an axial driving of the
tools into the rock to be machined, as
the machining tools are not effective at the face, by being covered by the lid
flange 75. This disadvantage
is avoided with the embodiment according to fig. 13, where two support
elements 73a, 73b are provided,
which support respectively every second machining tool at the circumference of
the spindle drum in a
star-shaped manner. The two support elements 73a, 73b are arranged with
different distances s, S from
the bearing flange 18 for this, and support the respective second bearings of
different tool spindles in
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star-shaped projecting arms 77. So that the spindle drum in the embodiment
according to fig. 12 or fig.
13 cannot sag due to the forces acting on the machining tools, the lid flange
75 or the support journal 72
can be provided with a bearing journal 86 arranged concentrically to the
spindle drum axis 34, shown
with dash-dot lines in the drawings for the additional support of the spindle
drum by means of a bearing
(not shown), which is for example present in the same machine frame as the
drum support at this
opposite side.
Finally, with the embodiment shown in fig. 14, the spindle drum 13 is,
additionally to the tool spindles
22, which are distributed evenly over its circumference with milling tools 41
arranged thereon, provided
with a core milling device 78 arranged on the inside of the pitch circle 19
described by the tool spindles,
which milling device is arranged with a small eccentricity e to the drum axis
34, and which is driven
opposite to the direction of rotation of the tool spindles. The core milling
device thereby consists of a
reception cartridge 79, on the inside of which is mounted a milling shaft 80
in a rotary manner, which
carries a milling head 81 at its front end pointing towards the rock. At its
rear end, which projects from
the reception cartridge 79, the milling shaft is provided with a front gear
wheel 82 which is flanged
thereon. The reception cartridge 79 with the shaft mounted therein is inserted
in a milling cutter reception
provided at the bearing flange 18 of the spindle drum 13 and is irrotationally
fixed. In the mounted
condition, the front wheel 82 meshes with an internally geared milling cutter
drive gear ring 83, which is
firmly mounted to the drum support 11 and which engages in a circumferential
groove 84 provided at the
rear side of the bearing flange of the spindle drum. The core milling cutter
is thereby driven in the
opposite rotary direction to the direction of rotation of the spindle drum and
favours in particular during
the axial driving-in of the tool into the rock the excavation of the material
possibly remaining in the
central area 85 described by the tool spindles.
The invention is not limited to the shown and described examples of
embodiments, but different changes
and additions are feasible, without leaving the scope of the invention. It is
for example possible to let the
tool spindles of a first group of tools and the tool spindles of a second
group of tools rotate in opposite
directions, in particular when the tools of the first group are provided on a
different pitch circle to those
of the second group. The details shown and described on the basis of the
individual embodiments can be
combined with one another in most diverse ways, which can be noted by the
expert without special
difficulties. With the selection of suitable machining tools it is easily
possible, to use the device
according to the invention also for the machining of other materials than rock
or coal, for example for the
machining of metal, wood or plastics.
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